Seals are used to fluidly seal interfaces, such as an interface between an engine block and a cylinder head of an internal combustion (IC) engine. Cylinder head seals (e.g., head gaskets) typically extend around cylinder bores of an IC engine to provide a combustion seal, which retains high temperature and high pressure gases within the cylinder bores. In addition, cylinder head seals (e.g., head gaskets or discrete seals) fluidly seal fluid transfer orifices that extend between the engine block and the cylinder head to communicate fluid (e.g., water, coolant, or oil) therebetween.
The interface between an engine block and a cylinder head is particularly difficult to seal for multiple reasons. For example, forces from the combustion process, especially for high combustion (e.g., diesel and natural gas) engines, force the engine block and the cylinder head apart, causing slight movement therebetween. In addition, that interface experiences significant thermal cycling due to the repeated heating and cooling of the engine. Further, the fasteners connecting the cylinder head to the engine block may be unevenly loaded, which can over-compress and/or under-compress certain portions of a cylinder head seal. Lastly, intake manifold overpressure (IMOP) events produce elevated peak cylinder pressures, which may result in charge leakage.
During IMOP events, charge leakage (e.g., high pressure exhaust gas) may travel through the interface between the cylinder head and the engine block and may leak into and/or damage one or more fluid transfer tubes, thereby contaminating the fluid (e.g., water, coolant, oil, etc.) contained therein. Such contamination can result in significant engine damage if not addressed immediately. To that end, some IC engines have replaced unitary cylinder head gaskets with a combustion seal and discrete fluid transfer tube seals. However, although certain combustion seals may survive an IMOP event without incurring damage, the individual fluid transfer tubes may incur damage from the charge leakage traveling through the interface. Furthermore, as the number of individual components increases, technicians may be more likely to forget to install one of the components during assembly or during a rebuild process. Additionally, while complicated valves are sometimes used to deal with IMOP events, such, valves may not respond to IMOP events fast enough, thereby causing significant engine damage.